An electronic video game is usually played by a user who interacts with a video game system through a user interface. Typically, the user reacts when there are visual activities displayed on an electronic video device such as a television screen. The “brain” of a video game system, also known as a platform, can be a personal computers or a video game console. The user interface, also known as a game controller, is typically a joystick used to give inputs to video games. The user interface can be different from platform to platform. For example, the number of buttons on a dedicated joystick may range from one to more than ten.
Beyond the common element of visual feedback, video games have utilized other means to provide interaction and information to the player. For example, sound effect is produced when there is a collision between a baseball bat and a baseball. On the other hand, when a reaction force is required to provide physical impact effect to a user when playing on a video game, for example, when a tennis ball is strike by a tennis racquet, a vibration on the game controller or handler is produced to emulate the impact reaction force.
Wii, designed by Nintendo, revolutionized video game's user interface. The key to Nintendo Wii's interface lies inside a controller. Instead of using a joystick to control the game, the primary control is the controller itself The controller contains solid-state accelerometers and gyroscopes that allow the controller to sense motions of the controller. A player holds the remote controller that maps a user's movement (the controller's movement actually) to joystick buttons. The video game system reflects the movement of the user by showing that on a display. The video game system also makes a reaction based on the algorithm stored in the system and shows that on the display accordingly.
When there is a collision between objects such as a baseball bat and a baseball, Wii makes impact effects by producing a “pop” sound and a vibration on the remote controller. However, the impact effects of Wii are not genuine since the “feel” of vibration is not comparable to the “feel” when one is using a real bat to hit a baseball because it does not reflect some important parameters, such as a reaction force applied on the hitter with a specific direction and strength. In addition, the user is expecting a feedback force when the ball is hit. If there is no such feedback force, the user may overuse his or her arm and that may cause injury to the user.
Using haptic peripherals to produce a reaction force such as that in video game arcade is not applicable to Wii since the remote controller is a free body and there is no physical contact between the remote controller and a solid reference such as the wall or the ground. Therefore, the arcade-type impact reaction force can not be provided on Wii.